QT 基于QScrollArea的界面嵌套移动

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在实际的应用场景中，经常会出现软件界面战场图大于实际窗体大小，利用QScrollArea可以为widget窗体添加滚动条，可以实现小窗体利用滚动条显示大界面需求。实现如下：

QT创建一个qWidget界面

在ui界面中利用QT自带的widget控件布局一个如下图所示的层叠关系，widget_2界面大小需大于widget大小

界面布局好后，将widget_2提升为类，提升之前需为工程新添加一个设计界面类，添加完之后，将widget_2提升为类类名和前面新添加的设计界面类名一致

源码实现如下

patchwindow.h

1 #ifndef PATCHWINDOW_H
2 #define PATCHWINDOW_H
3
4 #include <QDebug>
5 #include <QPainter>
6 #include <QWidget>
7 #include <QMouseEvent>
8 #include <QStyleOption>
9 #include <QPaintEvent>
10
11 enum CursorRegion{
12 NONE,
13 TOPLEFT,
14 TOPRIGHT,
15 BOTTOMRIGHT,
16 BOTTOMLEFT
17 };
18
19 namespace Ui {
20 class Patchwindow;
21 }
22
23 class Patchwindow : public QWidget
24 {
25 Q_OBJECT
26
27 public:
28 explicit Patchwindow(QWidget *parent = 0);
29 ~Patchwindow();
30 CursorRegion getCursorRegion(QPoint);
31
32 public:
33 int borderWidth;
34 int handleSize;
35
36 bool mousePressed;
37 QPoint previousPos;
38
39 private:
40 Ui::Patchwindow *ui;
41
42 protected:
43 void mousePressEvent(QMouseEvent*);
44 void mouseReleaseEvent(QMouseEvent*);
45 void mouseMoveEvent(QMouseEvent*);
46
47 signals:
48 void send_widget_rx_ry(int rx,int ry);
49 };
50
51 #endif // PATCHWINDOW_H

patchwindow.cpp

1 #include "patchwindow.h"
2 #include "ui_patchwindow.h"
3
4 Patchwindow::Patchwindow(QWidget *parent) :
5 QWidget(parent),
6 ui(new Ui::Patchwindow)
7 {
8 ui->setupUi(this);
9
10 this->setMouseTracking(true);
11
12 setFocusPolicy(Qt::StrongFocus);
13
14 mousePressed = false;
15 borderWidth = 1;
16 handleSize = 8;
17
18 }
19
20 Patchwindow::~Patchwindow()
21 {
22 delete ui;
23 }
24
25
26 //设置鼠标形状
27 CursorRegion Patchwindow::getCursorRegion(QPoint pos)
28 {
29 if (pos.x() > 0 && pos.x() < (handleSize + borderWidth) &&
30 pos.y() > 0 && pos.y() < (handleSize + borderWidth) ){
31 if (this->hasFocus())
32 this->setCursor(QCursor(Qt::SizeFDiagCursor));
33 return CursorRegion::TOPLEFT;
34 }
35
36 if (pos.x() > (this->width() - handleSize - borderWidth) && pos.x() < this->width() &&
37 pos.y() > 0 && pos.y() < (handleSize + borderWidth) ){
38 if (this->hasFocus())
39 this->setCursor(QCursor(Qt::SizeBDiagCursor));
40 return CursorRegion::TOPRIGHT;
41 }
42
43 if (pos.x() > (this->width() - handleSize - borderWidth) && pos.x() < this->width() &&
44 pos.y() > (this->height() - handleSize - borderWidth) && pos.y() < this->height() ){
45 if (this->hasFocus())
46 this->setCursor(QCursor(Qt::SizeFDiagCursor));
47 return CursorRegion::BOTTOMRIGHT;
48 }
49
50
51 if (pos.x() > 0 && pos.x() < (handleSize + borderWidth) &&
52 pos.y() > (this->height() - handleSize - borderWidth) && pos.y() < this->height() ){
53 if (this->hasFocus())
54 this->setCursor(QCursor(Qt::SizeBDiagCursor));
55 return CursorRegion::BOTTOMLEFT;
56 }
57
58 this->setCursor(Qt::ArrowCursor);
59 return CursorRegion::NONE;
60 }
61
62 void Patchwindow::mousePressEvent(QMouseEvent *event)
63 {
64 mousePressed = true;
65 previousPos = this->mapToParent(event->pos());
66 //qDebug()<<"previousPos = "<<previousPos;
67 }
68
69 void Patchwindow::mouseReleaseEvent(QMouseEvent*)
70 {
71 mousePressed = false;
72 }
73
74 void Patchwindow::mouseMoveEvent(QMouseEvent *event)
75 {
76 if (mousePressed){
77 QPoint _curPos = this->mapToParent(event->pos());
78 QPoint _offPos = _curPos - previousPos;
79 previousPos = _curPos;
80 //qDebug()<<"_offPos = "<<_offPos;
81 //qDebug()<<"_curPos = "<<_curPos;
82 emit send_widget_rx_ry(_offPos.rx(),_offPos.ry());
83 }
84 }

mainwindow.h

1 #ifndef MAINWINDOW_H
2 #define MAINWINDOW_H
3
4 #include <QMainWindow>
5 #include <QHBoxLayout>
6 #include <QDebug>
7 #include <QScrollArea>
8
9
10 namespace Ui {
11 class MainWindow;
12 }
13
14 class MainWindow : public QMainWindow
15 {
16 Q_OBJECT
17
18 public:
19 explicit MainWindow(QWidget *parent = 0);
20 ~MainWindow();
21
22 QScrollArea *m_pScroll;
23
24
25 private:
26 Ui::MainWindow *ui;
27
28 private slots:
29 void remove_widget(int r_x,int r_y);
30
31
32 };
33
34 #endif // MAINWINDOW_H

mainwindow.cpp

1 #include "mainwindow.h"
2 #include "ui_mainwindow.h"
3 #include <QPalette>
4
5 #include <QScrollBar>
6
7 MainWindow::MainWindow(QWidget *parent) :
8 QMainWindow(parent),
9 ui(new Ui::MainWindow)
10 {
11 ui->setupUi(this);
12 //this->resize(600,600);
13
14 //给父窗体填充颜色
15 QPalette palette = ui->widget_2->palette();
16 palette.setBrush(QPalette::Window,QBrush(QColor(61,61,61)));
17 ui->widget_2->setAutoFillBackground(true);
18 ui->widget_2->setPalette(palette);
19
20 ui->widget_2->setAttribute(Qt::WA_StyledBackground);
21 ui->widget_2->setStyleSheet("QWidget{background: black}");
22
23 ui->widget_3->setAttribute(Qt::WA_TransparentForMouseEvents, true);//设置该层鼠标事件透明，可以设置为显示层
24
25 m_pScroll = new QScrollArea(ui->widget);
26 m_pScroll->setWidget(ui->widget_2);//给widget_2设置滚动条
27 //ui->widget_2->setMinimumSize(1500,1000);//这里注意，要比主窗体的尺寸要大，不然太小的话会留下一片空白
28
29 QHBoxLayout *pLayout = new QHBoxLayout;
30 pLayout->addWidget(m_pScroll);
31 pLayout->setMargin(0);
32 pLayout->setSpacing(0);
33 ui->widget->setLayout(pLayout);
34
35 connect(ui->widget_2,&Patchwindow::send_widget_rx_ry,this,&MainWindow::remove_widget);
36
37 }
38
39 MainWindow::~MainWindow()
40 {
41 delete ui;
42 }
43
44 void MainWindow::remove_widget(int r_x,int r_y)
45 {
46 r_y = m_pScroll->verticalScrollBar()->value()-r_y;
47 r_x = m_pScroll->horizontalScrollBar()->value()-r_x;
48
49 if((0 < r_y) | (r_y == 0))
50 {
51 if(r_y > m_pScroll->verticalScrollBar()->maximum())
52 {
53 r_y = m_pScroll->verticalScrollBar()->maximum();
54 }
55 }
56 else
57 {
58 r_y = 0;
59 }
60
61 if((0 < r_x) | (r_x == 0))
62 {
63 if(r_x > m_pScroll->horizontalScrollBar()->maximum())
64 {
65 r_x = m_pScroll->horizontalScrollBar()->maximum();
66 }
67 }
68 else
69 {
70 r_x = 0;
71 }
72
73 m_pScroll->verticalScrollBar()->setValue(r_y);
74 m_pScroll->horizontalScrollBar()->setValue(r_x);
75
76 }